Xiphopenaeus Kroyeri Research Articles

ANALISIS DEL CONTENIDO ESTOMACAL DEL CAMARON TITI Xiphopenaeus kroyeri (HELLER) (CRUSTACEA: NATANTIA: PENAEIDAE)

Juveniles and adults of the seabob Xiphopenaeus kroyeri (Heller) were collected at monthly invervals between September 1988 and June 1988. The food items were determined in order of descending importance as: detritus and fragments of bivalve shells, polychaete worms, foraminiferans, and crustaceans. There was a difference in the feeding habits between the rainy seasson (September to December) and the dry season (January to June) with items like rotifers, sponges and radiolarians appearing only during the dry season. Analysis of the frequency of occurrence of different food items showed that groups like rotifers and bryozoans appear more frequently in juveniles. Measurements of protein and carbohydrate levels in the stomach contents revealed the highest peaks of proteins for adults in September (92.03 ug/mg dry weight of stomach contents) and for juveniles in December (81.27 ug/mg), and of carbohydrates for adults in October (45.81 ug/mg) and for juveniles in December (35.25 ug/mg). Quantitative differences in proteins and carbohydrates between the two size groups were not statistically significant.

Ray bycatch in a tropical shrimp fishery: Do Bycatch Reduction Devices and Turtle Excluder Devices effectively exclude rays?

Worldwide, many species of elasmobranchs (Chondrichthyes: Elasmobranchii) are currently threatened by marine fisheries activity and are on the Red List of the International Union for Conservation of Nature (IUCN). Although Bycatch Reduction Devices (BRDs) for teleost fish and Turtle Excluder Devices (TEDs) are now widespread in tropical shrimp trawling, information on their ability to mitigate bycatch of elasmobranchs, particularly rays (Batoidea), is scarce and limited to only a few isolated fisheries. The objective of this study was to evaluate the potential of trawls fitted with a square-mesh panel BRD and super-shooter TED in reducing ray bycatch. In this study, 65 catch-comparison hauls were conducted in the Atlantic seabob shrimp (Xiphopenaeus kroyeri) fishery off Suriname. Trawls with a BRD and TED combination reduced ray catch rate by 36%. A 21% reduction in mean size indicated the preferential exclusion of large rays. Hence, high escape ratios were observed for Dasyatis geijskesi (77%), a large-sized species, while exclusion of the small species Urotrygon microphthalmum was not significant, although their disc width is small enough to pass through the meshes of the BRD. Furthermore, a size-dependent escape for the two most abundant mid-sized ray species Dasyatis guttata and Gymnura micrura was observed. Exclusion-at-size differed for both species, however, likely related to species-specific morphology or behavior in response to the TED. This study shows that the combination of BRD and TED causes an important reduction in ray bycatch in seabob shrimp fisheries off Suriname. The great reduction in catch of large-sized rays is positive, but the mortality of juvenile rays is likely to have negative consequences for their populations. We therefore recommend gear-based and non-gear adaptations to further reduce the bycatch of small-sized rays.

Distribution patterns of the demersal fish fauna on the inner continental shelf of Suriname

This study aimed to characterise the spatio-temporal patterns of the demersal fish community in the shallow (<40 m) inner shelf waters of Suriname, based on (bi)monthly data for the period February 2012–April 2013. From 148 demersal trawl samples, distributed over 15 locations, 98 fish species were identified. Stellifer rastrifer, Amphiarius rugispinis and Cynoscion jamaicensis represented 50 % of the catches. Cluster analysis revealed three species assemblages, occurring in a nearshore–offshore depth gradient. A coastal fish assemblage occurred in the shallow turbid waters, characterised by muddy sediments with relatively high organic carbon content. A transition assemblage around 27 m water depth marked the shift towards a very different offshore fish assemblage on the deepest sampling locations (34 m), which were characterised by coarser sediments, with clear overlying waters. The coastal assemblage represented the ‘sciaenid community’ of tropical shelves, dominated by Sciaenidae and Ariidae. The offshore assemblage had a significantly lower fish density and diversity, and contained representatives of fish families typical for deeper tropical shelves, such as Paralichthyidae, Triglidae and Lutjanidae. The shift between the coastal and offshore fish assemblage was the most important feature of the demersal fish community, and coincided with a transition between two principal ecosystems: a coastal, river influenced system fuelled by detritus versus an open shelf system based on primary production. Whereas pelagic fishes are known to gain in importance on the open shelf, demersal fishes thrived in the coastal ecosystem, together with a potentially important epibenthic food source, the Atlantic seabob shrimp Xiphopenaeus kroyeri. In Suriname, large demersal (mainly sciaenid) fishes are the main fisheries resource for the artisanal fleet in the nearshore waters below 20 m depth. Because juveniles of commercially important fishes were abundant in our coastal trawl catches, we suggest the shallow nearshore waters have a main nursery function.

Spatio-temporal distribution patterns of the epibenthic community in the coastal waters of Suriname

This study aimed to characterize the spatio-temporal patterns of the epibenthic community in the coastal waters of Suriname. Data were collected on a (bi)monthly basis in 2012–2013 at 15 locations in the shallow (<40m) coastal area, revealing three spatially distinct species assemblages, related to clear gradients in some environmental parameters. A species-poor coastal assemblage was discerned within the muddy, turbid-water zone (6–20m depth), dominated by Atlantic seabob shrimp Xiphopenaeus kroyeri (Crustacea: Penaeoidea). Near the 30m isobath, sediments were much coarser (median grain size on average 345±103µm vs. 128±53µm in the coastal assemblage) and water transparency was much higher (on average 7.6±3.5m vs. 2.4±2.1m in the coastal assemblage). In this zone, a diverse offshore assemblage was found, characterized by brittle stars (mainly Ophioderma brevispina and Ophiolepis elegans) and a variety of crabs, sea stars and hermit crabs. In between both zones, a transition assemblage was noted, with epibenthic species typically found in either the coastal or offshore assemblages, but mainly characterized by the absence of X. kroyeri. Although the epibenthic community was primarily structured in an on-offshore gradient related to depth, sediment grain size and sediment total organic carbon content, a longitudinal (west-east) gradient was apparent as well. The zones in the eastern part of the Suriname coastal shelf seemed to be more widely stretched along the on-offshore gradient. Although clear seasonal differences were noted in the environmental characteristics (e.g. dry vs. rainy season), this was not reflected in the epibenthic community structure. X. kroyeri reached very high densities (up to 1383ind1000m−²) in the shallow coastal waters of Suriname. As X. kroyeri is increasingly exploited throughout its range, the current study provides the ecological context for its presence and abundance, which is crucial for an ecosystem approach and the sustainable management of this commercially important species and its habitat.

Reproductive ecology of the seabob shrimp Xiphopenaeus kroyeri (Heller, 1862) in a coastal area of Southern Brazil

The predictability of certain environmental factors that affect the life cycle of the seabob shrimp Xiphopenaeus kroyeri (Heller, 1862) was evaluated in a study of its reproductive biology in an area adjacent to Babitonga Bay, State of Santa Catarina, Brazil. Monthly sampling was conducted from July 2010 through June 2011 at depths of 5, 8, 11, 14, and 17 m. 76 004 individuals were obtained, with a pronounced peak in absolute abundance in austral autumn (34 208), coinciding with the annual closed season from March to May. Grain size composition of the sediment showed the closest relationship to the distribution of individuals (multiple linear regression, P <0.05), related to their burying habit. The observed correlations between the abundance of reproductive males (bearing spermatophores) and females with spent gonads (cross-correlation, P <0.05), and between reproductive males and reproductive females (with a 1-month lag) suggest that the peak of reproductive males preceded the peak of female ones. This result agrees with the pattern expected for females, which copulate in post-ecdysis (spent gonads). Spawning seemed to take place at greater depths, as evidenced by the concentration of reproductive females in these areas. The reproductive activities observed here confirm that this species follows a tropical/subtropical reproductive pattern, spawning continuously throughout the year, with the highest peaks in spring and autumn. The data indicate that the juvenile recruitment period observed in August-September resulted from the reproductive output noted in April–May. Additionally, the reproductive period recorded in November led to the juvenile peak observed in March–May.

Bycatch fauna of seabob shrimp trawl fisheries from Santa Catarina State, southern Brazil

Marine communities in tropical regions contain a great diversity of species that play key roles in ecological processes. The observed bycatch fauna in artisanal fishing for the seabob shrimp Xiphopenaeus kroyeri (Heller, 1862) in the southwest Atlantic exceeds the quantity of commercial shrimp captured. This bycatch has not been previously inventoried extensively in Brazil, particularly in the State of Santa Catarina, where small-scale shrimp fisheries is a traditional activity and dominates the local fishing economy. Six municipalities were sampled three times a month, from 1996 to 2011, yielding 216 species belonging to the bycatch (7 cnidarians, 22 mollusks, 42 crustaceans, 11 echinoderms, and 134 fishes). Bycatch management is a pressing aspect of shrimp fisheries. By inventorying the accidental bycatch, we provide a preliminary step towards defining intervention measures to reduce or make better use of this bycatch in seabob artisanal fisheries. Conservation of marine biodiversity is still inadequate in Brazil. We have attempted to identify additional threats to vulnerable and endangered species resulting from shrimp trawling.

Lifespan and reproductive dynamics of the commercially important sea bob shrimp Xiphopenaeus kroyeri (Penaeoidea): synthesis of a 5-year study

Population parameters of the shrimp Xiphopenaeus kroyeri (Heller, 1862) (sex ratio, length-frequency distributions (carapace length, CL), growth, lifespan, size of sexual maturity, spawning and recruitment) were analyzed in a long-term study from January 1998 through June 2003. The data on these parameters were collected and analyzed to test the hypothesis that the main period of juvenile recruitment in the bay coincides with the period of fishery closures currently designated by the Brazilian Institute of Environment and Renewable Natural Resources. Monthly collections were conducted along the southeastern Brazilian coast, using a shrimp fishing boat with “double-rig” nets sampling at stations up to 40 m depth. Sex ratios were female-biased only in zones with high reproductive activity such as in stations deeper than 15 m (χ2 test, p<0.05). The mean size of males and females was 15.3 ± 3.1 mm CL and 16.2 ± 4.7 mm CL, respectively, with size at sexual maturity estimates (CL50) of 14.8 mm for males and 15.5 mm for females. Mean growth curves provided estimates of CL∞ = 29.31 mm, k = 0.009/day, t0=−0.25 and CL∞ = 35.33 mm, k = 0.006/day, t0=−0.23 for males and females, respectively, and average lifespans of 1.35 for males and 2.12 years for females. Recruitment and abundances of reproductive females were highly correlated with the environmental factors such as higher water temperature and finer-grained bottom sediment (canonical correlation, r=0.63, p<0.001). The reproductive peaks in February-April 1998, March-May 1999 and February-May 2002 were followed by recruitment peaks in May-July 1998, July-September 1999 and April-June 2002, respectively. Thus, the proposed period of fisheries closure (March to May) does not coincide with the main recruitment periods observed for X. kroyeri.

A kinetic characterization of (Na+, K+)-ATPase activity in the gills of the pelagic seabob shrimp Xiphopenaeus kroyeri (Decapoda, Penaeidae).

We characterize the kinetic properties of a gill (Na(+), K(+))-ATPase from the pelagic marine seabob Xiphopenaeus kroyeri. Sucrose density gradient centrifugation revealed membrane fractions distributed mainly into a heavy fraction showing considerable (Na(+), K(+))-ATPase activity, but also containing mitochondrial F0F1- and Na(+)- and V-ATPases. Western blot analysis identified a single immunoreactive band against the (Na(+), K(+))-ATPase α-subunit with an Mr of ≈ 110 kDa. The α-subunit was immunolocalized to the intralamellar septum of the gill lamellae. The (Na(+), K(+))-ATPase hydrolyzed ATP obeying Michaelis-Menten kinetics with VM = 109.5 ± 3.2 nmol Pi min(-1) mg(-1) and KM = 0.03 ± 0.003 mmol L(-1). Mg(2+) (VM = 109.8 ± 2.1 nmol Pi min(-1 )mg(-1), K0.5 = 0.60 ± 0.03 mmol L(-1)), Na(+) (VM = 117.6 ± 3.5 nmol Pi min(-1 ) mg(-1), K0.5 = 5.36 ± 0.14 mmol L(-1)), K(+) (VM = 112.9 ± 1.4 nmol Pi min(-1 )mg(-1), K0.5 = 1.32 ± 0.08 mmol L(-1)), and NH4 (+) (VM = 200.8 ± 7.1 nmol Pi min(-1 )mg(-1), K0.5 = 2.70 ± 0.04 mmol L(-1)) stimulated (Na(+), K(+))-ATPase activity following site-site interactions. K(+) plus NH4 (+) does not synergistically stimulate (Na(+), K(+))-ATPase activity, although each ion modulates affinity of the other. The enzyme exhibits a single site for K(+) binding that can be occupied by NH4 (+), stimulating the enzyme. Ouabain (KI = 84.0 ± 2.1 µmol L(-1)) and orthovanadate (KI = 0.157 ± 0.001 µmol L(-1)) inhibited total ATPase activity by ≈ 50 and ≈ 44 %, respectively. Ouabain inhibition increases ≈ 80 % in the presence of NH4 (+) with a threefold lower KI, suggesting that NH4 (+) is likely transported as a K(+) congener.

POPULATION BIOLOGY OF SEABOB-SHRIMP Xiphopenaeus kroyeri (Heller, 1862) CAPTURED ON THE SOUTH COAST OF PERNAMBUCO STATE, NORTHEASTERN BRAZIL

This paper aims to describe the population dynamics and to evaluate the stock of the seabob-shrimp Xiphopenaeus kroyeri on the coast of Pernambuco. Sampling was carried out between August/2011 and July/2012 in Sirinhaém, southern coast of Pernambuco. A total of 1201 individuals were analyzed, 673 females and 528 males. Total length (Lt) of females varied from 4.5 to 13.5 cm while the Lt of males ranged between 4.0 and 11.0 cm. The relationship between the Lt and carapace length and Lt and total weight showed negative allometry (males, females and pooled sexes). The slope of the curve "b" was statistically different between males and females for both relationships. Females mature with 8.90 cm. Asymptotic length L∞ was lower for males than for females (12.26 to 14.79 and 10.72 to 11.5 cm, respectively), K was similar between sexes (1.00-2.04 and 1.00-2.63 cm/year-1 respectively) as well as the longevity and size at 1st capture (1.50 to 1.97) years and 7.9 to 8.9 cm for males and females, respectively). The results indicate that X. kroyeri in the region is not overexploited for males, however considering females and pooled sexes the stock is near to being fully exploited.

Sternal spines in penaeid postlarvae (Decapoda: Penaeidae): life-phase-specific and systematically significant?

Our ability to identify and discriminate postlarvae of penaeids below family level remains poor due to phase brevity and a lack of taxonomic characters. Whether sternal spines are unique and taxonomically significant to postlarvae has not been resolved. I describe number and placement of spines in Parapenaeus sp. Smith, 1885, and a specimen tentatively identified as Xiphopenaeus kroyeri (Heller, 1862) from the Gulf of Mexico; review information for penaeids worldwide; and evaluate the significance of sternal spines as a life-phase specific taxonomic character and to penaeid systematics. To date, sternal spines have been described for 14 of 32 genera and 26 species. Most taxa share one of two common sternal formulas: either 0 + 0 + 0 + 1 + 0, or 0 + 0 + 0 + 1 + 1. Only Metapenaeopsis Bouvier, 1905, and the tentative Xiphopenaeus kroyeri have a pair of spines on at least the first-two sternal plates, and only Metapenaeopsis and Litopenaeus Perez-Farfante, 1969, contain members with different sternal formulas. I suggest that differences among taxa in shape of the sternal plates may be an unrecognized taxonomic character. Sternal spines are not life-phase specific and do not reflect lower-level systematic relationships within Penaeidae regardless of generic nomenclature applied. The unusual length, shape, and reverse orientation of the spine on plate five in species of Parapenaeus, and presence of an elongate ventromedian spine on one or more pleomeres in Parapenaeus and Funchalia Johnson, 1868, supports molecular and morphological data that Penaeidae may be paraphyletic. While generally ineffective as a stand-alone taxonomic character, differences in number, placement, and orientation of sternal spines, i.e., the ‘sternal pattern’; knowledge of geographic distributions; and, perhaps differences in sternal plate shape should be included in the suite of characters used to discriminate and identify penaeids during the postlarva phase.

Annual, seasonal and spatial abundance of the seabob shrimp Xiphopenaeus kroyeri (Decapoda, Penaeidae) off the Southeastern coast of Brazil.

We investigated the influence of environmental factors in spatial and temporal distribution of the seabob shrimp Xiphopenaeus kroyeri in Santos Bay and São Vicente Estuary, state of São Paulo, Brazil. Monthly samples were obtained, from May 2008 through April 2010, from four locations in the estuary and four in the bay. No individual was collected in the estuary and this was attributed to the low salinity means recorded in this environment. We collected 109,153 individuals in the bay and there was no difference in abundance between the two years comprised by the study period. The similarity in spatial distribution can be related to sediment grain size that in all sampling locations showed great amount of very fine sand. The largest amount of reproductive females was obtained in early 2010, when temperature was high, and this could have increased the juvenile recruitment in April 2010. According to our results, the distribution of X. kroyeri in the study area is influenced by temperature, which is related to reproduction, and salinity, limiting the entrance of individuals in the estuarine region.

Long-term patterns of spatial and temporal distribution in the seabob shrimp Xiphopenaeus kroyeri (Decapoda: Penaeidae) population in southeastern Brazil

The effect of some environmental factors on the distribution and abundance of different demographic categories of Xiphopenaeus kroyeri (Heller, 1862) was tested for three 12-month periods over 13 years in Ubatuba Bay, Sao Paulo State, southeastern Brazil. Four sites with different characteristics were sampled monthly from January to December 1998, July 2006 to June 2007 and September 2010 to August 2011. Bottom water temperature and salinity samples were taken monthly, and one sediment sample from each site was taken during each period. Although total abundance, as the number of adult males and non-reproductive females did not differ among periods, in 1998 the abundance of juveniles was greater and reproductive females was lower than the other two periods. The high abundance of juveniles in 1998 was associated with the high frequency of optimal temperatures for juvenile’s metabolism and this environmental variable can influence the abundance of individuals among years. Adult shrimp can be established in sites with variations in sediment grain size composition, whereas juveniles are more abundant in sites with finer sand. We suggest that areas with high juvenile abundance in Ubatuba Bay must have controlled exploitation and that the fishery can be focused on the deepest areas, where adults are predominant.

Haplotype-specific single-locus multiplex PCR assay for molecular identification of sea-bob shrimp, Xiphopenaeus kroyeri (Heller, 1862), cryptic species from the Southwest Atlantic using a DNA pooling strategy for simultaneous identification of multiple samples

This work describes a single-locus multiplex PCR assay based on partial COI mitochondrial gene polymorphisms for identification of two Atlantic cryptic species of the sea-bob shrimp, Xiphopenaeus kroyeri (Heller, 1862) that were recently identified using molecular approaches. Reliable identification of cryptic species of Xiphopenaeus spp. has fundamental implications for management and conservation of the sea-bob shrimp fishery stocks. The assay was developed based on sequence polymorphisms of 130 specimens of both species, comprising samples from Venezuela to the southern coast of Brazil, validated by the amplification of 368 adult shrimp samples from nine different locations and confirmed by direct sequencing. The methodology has been optimized to enable the identification of equi-molar mixtures of DNA from up to 10 individuals by PCR reaction, allowing the fast and cheap identification of many specimens for large scale studies on fisheries biology and population genetics. The DNA pooling strategy enabled the identification of a new locality of occurrence of Xiphopenaeus sp. II in the Brazilian coast, Caravelas, indicating that the species distribution may be continuous on the coast, and not disjoint as observed so far.

Impact of smoking on the lipid fraction and nutritional value of seabob shrimp (Xiphopenaeus kroyeri, Heller, 1862)

The impact of smoking on the lipid fraction of seabob shrimp (Xiphopenaeus kroyeri, Heller, 1862) was evaluated by the formation of cholesterol oxides and changes in fatty acid composition and in nutritional quality. In addition, cholesterol and chloride contents, pH, and proximate composition were determined. Smoking reduced lipid and protein contents and increased ash and chloride concentrations, while the pH value remained constant. Despite the loss of 18:2n6 (53%), 20:4n6 (50%), 22:6n3 (49%), 20:5n3 (47%) and 18:1n9 (44%), the n6/n3 ratio did not change significantly. The index of atherogenic (0.82) and of thrombogenic (0.62) were low after smoking. Smoking also caused losses of cholesterol (27%) and 7β-hydroxycholesterol (50%), while 7-ketocholesterol and 7α-hydroxycholesterol contents remained constant.

Evaluation of determinants of Xiphopenaeus kroyeri (Heller, 1862) catch abundance along a Southwest Atlantic subtropical shelf

Abstract Generalized linear models were applied to identify factors affecting the capture rates (catch per unit effort, cpue) of Xiphopenaeus kroyeri and to estimate time-series data with standardized abundance indices. The adjusted models revealed that the most powerful vessels (with greater HP) were up to 3.5 times more efficient than vessels with less powerful engines. The seasonal variation of the resource changed from year to year, most likely due to variations in the recruitment season and the timing of temporary fishing bans. The variation of cpue was similar between the northern and southern sectors of the study area. In these, X. kroyeri abundances increased in the years 1996, 1997, 2001 and 2002, while in the central sector, the cpue fluctuated with a period duration of approximately two years. During the period, the relative abundance of the species displayed neither a decreasing nor an increasing trend, indicating that this has been harvested at stable levels. However, X. kroyeri stock was reduced by overfishing during the 1980s and exhibits variations in abundance that may occur in response to environmental fluctuations; thus, the harvesting of this species should be managed with extreme caution.

Characterization socio-economic of the artisanal fishing of the sea-bob shrimp in Porto Belo, SC

The artisanal fishing for the sea-bob shrimp (Xiphopenaeus kroyeri) has been practiced on the Santa Catarina coast since 1960, always using the method of motorized dragnet with rings, where it generates jobs and income, and helps keep the traditional Azorean cultural tradition alive. The socio-economic characteristics of the artisanal fishing were conducted by semi-structured interviews with 31 surveys applied to fishermen to July 2010/June 2011. The interviewees were between 28 and 63 years, married (80.6%), with incomplete elementary education (61.3%); around 65.0% had been working in the activity for more than 30 years. They use, own boats (93.5%), length 7.0-11.5 m, with cabin (83.9%), Yanmar 18 HP motor (61.3%), nets of 11.0-15.4 m (90.3%) and mesh size of 3-4 mm (58.1%). They fish over a wide territory, from Sao Francisco do Sul to Florianopolis. The normal working day is between 10-14 hours day-1, 4-6 days week-1 (80.6%), from 6-8 months year-1, at depths of 2-33 m. The minimum capture of shrimp is between 0.5-10.0 kg day-1 and the maximum is 230-1,200 kg day-1, giving a gross monthly income of 1-2 minimum salaries (67.7%).

A contribuição da genética no estudo das populações de camarão sete-barbas do litoral brasileiro

Genetic studies can provide several important informations for sustainable fisheries management, mainly for the identification of different genetic stocks. In Brazil, genetic studies of the sea-bob shrimp, Xiphopenaeus kroyeri, produced important new information on the systematics of the genus, demonstrating the presence of anonymous cryptic species and outlining their geographical distribution and the levels of genetic diversity and population structuring of Brazilian species. Allozymes and sequence polymorphisms of the mitochondrial COI gene have also been used to beget diagnosis systems for the correct species identification. Recently, geometric morphometrics emerged as a powerful methodology for identifying operational taxonomic units, confirming genetic data with great similarity of results, and representing a promising tool to assist the identification of fishery stocks. Geometric morphometrics analyses were used to characterize Xiphopenaeus samples from Brazil, showing significant differences among populations, confirming previous patterns revealed by molecular data. This study gathers the information produced so far about the molecular systematics, patterns of geographic distribution of the cryptic Xiphopenaeus species, genetic and morphometric characterizations of variability and delineation of population boundaries. It intends to determine distribution and structuring consensus patterns of the genetic variability, aiming to support management and conservation actions as well as to identify gaps of knowledge and direct future efforts in order to address them.

CPUE study on seabob shrimp fisheries of São Paulo state from 2000 to 2011

Seabob shrimp ( Xiphopenaeus kroyeri ) fishery is operated all over the coast off Sao Paulo State. For that reason the management and supervision of those catches is necessary in order to assure the maintenance of the stocks and the stability of that activity. This paper aims to contribute to the management of the resource through the analysis of the landing dynamics of the species caught off the coast of S a o Paulo State from 2000 to 2011. The activity is operated by a fleet considered industrial, that comprises 15% of the productivity units and contributes with 47% of the landing production, and by an artisanal fleet that corresponds to 85% of all the productivity units and 53% of the landed shrimp. The CPUE (Catch per Unit Effort) analysis shows stability through the abundance indicator in the last years. The decrease on the number of units from the industrial fleet, probably due to the fisheries low profitability, was the most probable cause for the CPUE stability, or the fishing effort has not exceeded the sustainability limit of the seabob shrimp stock off Sao Paulo State. The observed stability in the abundance indicator is a very promising factor, and it can modify the vision of the status of the resource in different sectors of the fisheries management. It can also influence management measures that must be established with the participation of the artisanal sector, due to the contribution that the artisanal fleet presents in numbers of productivity units and in the percentage of the total of shrimp landing. That participation, although necessary, has not occurred yet.

Efeito do cádmio e zinco na excreção de amônia e consumo de oxigênio do camarão sete-barbas, de acordo com a temperatura

Penaeid shrimps are important resources for worldwide fisheries and aquaculture. In Brazil, Xiphopenaeus kroyeri is an important commercially exploited species, and is an ideal animal for studying the impairment caused by the effects of heavy metals that are often detected in coastal areas. The main purpose of the present study was to detect the acute toxicity of Cd and Zn to X. kroyeri and to investigate their effects on oxygen consumption and ammonium excretion in different temperatures (25 oC, 20 oC, 15 oC), which have not been carried out in this species before. First of all, we examined the acute toxicity of Cd and Zn to X. kroyeri 24, 48, 72, and 96-h medium lethal concentration (LC50). Furthermore, we also found that exposure of shrimp to Cd and Zn caused an inhibition in oxygen consumption of 52.50% and 52.63%, respectively, relative to the control. However, after separate exposure to Cd and Zn, elevations in ammonium excretion were obtained, which were 85.00% and 89.47% higher than the control, respectively. The results shown that Cd and Zn performs higher toxicities to X. kroyeri at higher temperature.

Spatial and temporal distribution of the captures of seabob shrimp, in the Armação do Itapocoroy, Penha, SC

Xiphopenaeus kroyeri is considered to be overfished in the southern and southeastern regions, due to intensive fishing, with juveniles being caught in shallower waters, near beaches, in bays and inlets, whilst adults occur at depths of about 20 m. This study aims to analyze the space/time distribution of captures of sea-bob-shrimp in the ship-yard/surfzone of the Armacao do Itapocoroy, Penha, SC, during one full year. Monthly catches (one sample being divided in two), lasting 15 minutes, were undertaken at depths of 10, 20 and 30 meters between July 2010 and June 2011, using a whaling-boat. The population of X. kroyeri presented seasonal variations, the greatest concentrations and adults were observed at 20 metres. The rare caught at 30 meters front of the high sampling effort indicated that the species probably doesn’t use this isobath as living area in the study region. The action of the fishing fleet in the shallower areas in Armacao Itapocoroy, mainly during recruitment which starts in November, raises concern about the maintenance of species stocks, given the high abundance of juveniles in these shallow sites and their importance in the continuity of this kind of fisheries.